This demonstration project will (1) implement an Intensive Case Management (ICM) program for a large heterogeneous sample of homeless clients with alcohol or other drug problems, (2) document each stage in the process of service delivery to these clients, (3) assess the effectiveness of the ICM program using an experimental design in which clients are randomly assigned to experimental and control conditions, and (4) actively participate in the national evaluation of the demonstration projects supported by these cooperative agreements. The effects of the proposed ICM program will be assessed on an extensive range of client outcomes including: use of alcohol and other drugs, residential stability (including alcohol and drug-free residences), physical and mental health, employment and educational level, and quality of life. The ICM program will be implemented in a setting that already offers a comprehensive array of services to the homeless. These services include a multifaceted outreach program (including both mobile response and a drop-in center with separate facilities for men and women), a continuum of substance abuse treatments (including detoxification, residential, and outpatient services), literacy and vocational assessment, job training and placement, and a range of housing options from transitional to permanent residences with varying degrees of autonomous living. The ICM program will provide direct services and also broker an extensive array of services to homeless clients throughout their enrollment in the service programs, from needs assessment to placement in housing. A core team of six case managers will work in dyads with a maximum caseload of 17 clients per dyad. The case managers' activities will be aimed at tailoring service delivery to client needs, increasing the level and quality of services received, improving continuity of service, facilitating systems linkages. Obtaining and placing clients in stable, alcohol and drug-free housing will be a top priority. The effects of ICM will be assessed by comparing clients who receive ICM to randomly-equivalent clients who do not receive ICM but who have access to all of the other services except ICM.